Abstract
Oil film thickness and traction characteristics of a polyol ester in some hydrofluoro carbon and hydrochlorofluoro carbon refrigerants are determined with an EHD tester, where increase in refrigerant gas pressure decreases film thickness as well as traction in each refrigerant. When compared under an identical gas pressure, the film thickness with refrigerant is R-125 > R-134a > R-22, while that for the coefficient of traction at a certain slide-roll ratio is the same as film thickness. Oil film formability and traction performance are inversely correlated with solubility of refrigerant in POE in mole concentration.